On the utility of S-mesitylsulfinimines for the stereoselective synthesis of chiral amines and aziridines

The synthetic utility of S-mesitylsulfinimines for the synthesis of chiral amines and aziridines was examined through their reactions with Grignard reagents, with the ylides derived from trimethylsulfonium iodide and S-allyl-tetrahydrothiophenium bromide and through an aza-Darzens manifold, affording convenient access to a diverse range of highly substituted chiral amines and aziridines in high yields and excellent stereoselectivities.     

Metal-biomolecule frameworks (MBioFs)

Biomolecules are the building blocks of life. Nature has evolved countless biomolecules that show promise for bridging metal ions. These molecules have emerged as an excellent source of biocompatible building blocks that can be used to design Metal-Biomolecule Frameworks (MBioFs). This feature article highlights the advances in the synthesis of this class of MOFs. Special emphasis is provided on the crystal structures of these materials, their miniaturization to the submicron length scale, and their new potential storage, catalytic, and biomedical applications.     

Preparation of Co:TiO2 thin films by crossed-beam pulsed laser deposition

Co:TiO₂ thin films were deposited using two interacting plasmas produced from different targets, TiO₂ and cobalt. By keeping constant the laser ablation conditions on the TiO₂ target and changing them on the Co target, it was possible to vary in a controlled way the Co content in the films. The cobalt plasma parameters, such as the ion kinetic energy and plasma density, were determined for each deposition condition in an attempt to correlate them with the material’s properties. The cobalt ion mean kinetic energy was varied from 36 to 789 eV, resulting in films with Co content from 1.2 up to 5.1 at.%, respectively, revealing that the cobalt content can be controlled by the Co⁺ kinetic energy. The study of the optical properties showed that the optical band gap decreased from 2.9 to 2.0 eV as the Co content increased. Raman spectroscopy was used to characterize the microstructure of the deposits, and the obtained results suggest the formation of two coexisting phases: TiO₂ in its rutile phase and CoTiO₃. It was found that as the Co⁺ energy increases, the CoTiO₃ phase develops in a greater quantity. XPS measurements confirm the Raman spectroscopy results.     

Relative quantum yield for the production of O-atom and S-atom from the photodissociation of OCS in the vacuum UV

The relative efficiencies for two dissociative channels in the vacuum UV photolysis of carbonyl sulphide have been determined using the flash photolysis-resonance fluorescence technique to measure initial yields of atomic oxygen and atomic sulphur. At wavelengths above 105 nm, the dissociation of OCS to form atomic sulphur exceeded that for the formation of atomic oxygen to such an extent that only an upper limit could be placed on the minor process, Φ_S >/ 50 Φ_O. In addition, the flash photo-excitation of carbonyl sulphide produced a long-lived spontaneous emission in the UV and vacuum UV that might be due to molecular fluorescence from OCS.     

The vacuum ultraviolet spectra of HCN,C2N2, and CH3CN

Quantitative vacuum ultraviolet absorption spectra for HCN, C₂N₂, and CH₃CN have been obtained over the wavelength range 60 nm ? λ ? 160 nm. Where comparison is possible, our measurements of the absorption coefficients for HCN and C₂N₂ are consistent with previous studies. Because of the superior resolution of this work (0.05 nm), vibrational assignments in the valence and Rydberg transitions of HCN have been extended while higher members of the Rydberg series in CH₃CN have been identified.     

Synthesis of heavily substituted 1,2-amino alcohols in enantiomerically pure form

[reaction: see text] A simple and convenient methodology for the preparation of optically pure 2-amino-2-aryl-1,1-diphenylethanols is presented. Allylamine was found to produce the ring-opening of triaryloxiranes in a regioselective and a stereospecific fashion. Removal of the allyl protecting group provided the free 1,2-amino alcohols in enantiomerically pure form.     

Recent applications of conductivity detection in capillary and chip electrophoresis

The review provides a comprehensive survey of the recent applications of contact and contactless conductivity detection in capillary electrophoretic and chip electrophoretic analyses of a broad scale of compounds, from low-molecular-mass highly mobile small inorganic and organic ions, via medium-molecular-mass peptides and oligo- and polynucleotides up to high-molecular-mass biopolymers, proteins and nucleic acids fragments. The review presents also the recent developments in the construction of different types of conductivity detectors (detectors with galvanic contact of the sensing electrodes with the BGE and sample components, contactless conductivity detectors with capacitively coupled tubular and semitubular electrodes and combined conductivity/optical detectors) applied in the capillary electromigration methods performed in classical fused silica, polytetrafluorethylene, and polyetheretherketone capillaries or on glass and polymethylmethacrylate microchips. In addition, the principle and theoretical bases of conductivity detection in capillary electromigration techniques, zone electrophoresis, ITP, micellar EKC, and electrochromatography are briefly described.